Device for administering a product in doses

ABSTRACT

A device for administering an injectable product in doses including a casing having a receptacle for a container which contains the product and accommodates a piston such that the piston can advance towards an outlet for delivering a selected product dosage, a dosing member, with which a dosing movement can be performed relative to the casing for selecting the product dosage, a drive unit, which can be coupled to the casing and the dosing member such that the drive unit can be adjusted relative to the casing from a dosing starting position to a dosing end position by the dosing movement of the dosing member, an operating mechanism which causes the drive unit to perform a delivering movement by which the piston is advanced towards the outlet, and a restoring spring, which is secured in a tensioned state and is coupled to the drive unit by a release for causing a restoring movement of the drive unit towards its dosing starting position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International ApplicationPCT/CH01/00468, filed on Jul. 31, 2001, which claims priority to GermanPatent Application DE 100 46 279, filed on Sep. 19, 2000, the contentsof which are hereby incorporated in their entirety by reference.

BACKGROUND

The invention relates to a device for administering an injectableproduct in doses, comprising a dosing means which can be restored orreset in accordance with a selected product dosage to be administered.

In known injection devices, for example comprising spindle drives ortoothed rack drives, restoring or resetting the dosing means is eithervery awkward or not possible at all for a user of the device. Restoringcan for example make exchanging an emptied product container easier, asis described in EP 0 614 386 B1. To this end, a toothed rack which actson a piston arranged in the container is only provided with teeth over aportion of its perimeter. The teeth of the toothed rack cooperate withopposing teeth in such a way that it is possible to slide the toothedrack in discrete increments, for the purpose of delivering product, butthe toothed rack is prevented from simply retracting. In order torestore the toothed rack, it is formed such that the teeth and theopposing teeth can be disengaged by rotating the toothed rack by 90° andthe toothed rack can then be manually retracted and moved to a startingposition for another dosed delivery. Restoring the driven memberrequires a user to perform a number of movements in coordination. Whenadministering medically active products, a preferred use or area ofapplication for the invention, this may be particularly difficult forusers who may be suffering from fine motor disorders.

SUMMARY

It is an object of the invention to enable a device for administering aninjectable product in doses to be restored or reset using as little andas simple handling as possible.

In devices such as the invention relates to, a container is accommodatedin a casing, said container containing the product and accommodating apiston which can slide towards a container outlet in order to deliver aselected product dosage. A dosing member and a drive unit cooperate toselect the product dosage. To select the product dosage, the dosingmember performs a dosing movement relative to the casing. The drive unitis coupled to the casing and to the dosing member such that the dosingmovement of the dosing member causes an adjusting movement of the driveunit from a dosing starting position to a dosing end position, relativeto the casing. The device further comprises an operating means whichcauses the drive unit to perform a delivering movement by which thepiston is advanced towards the container outlet and the selected productdosage is thereby delivered and administered.

In one embodiment, the adjusting movement of the drive unit from thedosing starting position to the dosing end position or at least towardsthe dosing end position is preferably a purely adjusting movementseparate from the delivering movement, relative to the casing andrelative to the piston. The separate adjusting movement reduces a slightgap between the piston and a driven member of the drive unit in a dosingposition of the device. During the delivering movement, the drivenmember presses against the piston. Instead of moving the driven memberrelative to the piston as the adjusting movement, however, the adjustingmovement can also be performed by another member of the drive unit,which performs the delivery movements together with the driven member,relative to the driven member. It is also possible for the dosing memberto perform the adjusting movement, by performing an adjusting movementrelative to a mechanical stopper on the casing side at the same time asits dosing movement, thus defining a stroke of the delivering movement.In this embodiment, the dosing member would also be a component of thedrive unit, since it participates in the delivering movement of thedrive unit. Separating the adjusting movement and the deliveringmovement enables the dosage to be particularly reliably selected.Furthermore, the delivering movement can always remain the same. Spindledrives in particular have proven effective for this preferred type ofdosing. Although less preferred, the adjusting movement and thedelivering movement can also be combined, for example if the productdosage is selected even as the delivering movement is being performed,as is possible with a drive unit formed as a toothed rack drive.

In accordance with the invention, the device comprises a restoringspring which is secured when tensioned and is coupled to the drive unitby a release. Due to the coupling, the released spring energy causes arestoring movement of the drive unit towards its dosing startingposition. It is only necessary to release the safety on the restoringspring, which can be done with just one hand by simply pressing a buttonor sliding a slider.

In some embodiments, the device can be provided, already with atensioned restoring spring, by a manufacturer, such that the restoringspring is only released when required. In other preferred embodiments,the restoring spring is tensioned when the drive unit is adjustedtowards its dosing end position. In this case, a locking means isprovided which allows the adjusting movement but prevents the drive unitfrom being inadvertently retracted towards its dosing starting positionby the effect of the restoring spring. The restoring spring preferablyacts on the drive unit via the dosing member. The locking means alsopreferably acts on the dosing member.

In one preferred embodiment, the restoring spring is formed by amechanical spring, for example a spiral spring. If a member of the driveunit is rotated relative to the casing for the purpose of adjusting thedrive unit, then the spiral spring can be clamped between the casing andsaid member of the drive unit. More preferably, such a spiral spring isclamped between the casing and the dosing member, which in this case ismounted such that it can rotate relative to the casing, in order toperform the dosing movement.

In some preferred embodiments, the drive unit is a spindle drive. Arotational movement of the dosing member is introduced into the spindledrive, and the spindle drive performs the adjusting movement. Inparticular, the spindle drive can be formed multi-staged, such as isdescribed in WO 98/47552, the disclosure of which is hereby referencedand incorporated by reference with respect to advantageous spindledrives and also, more generally, with respect to advantageous,multi-stage drive units.

Advantageously, in some embodiments, the restoring spring can only beused to restore the drive unit to a dosing starting position assumedbefore it is first adjusted. If a spindle drive is used, then reversingthe drive unit, which is often regarded as cumbrous but which isimperative for reusing the device, can be omitted.

Alternatively, an inadvertently selected overdose can be reliablycorrected using the restoring spring in accordance with the invention.In some particularly preferred embodiments, the restoring spring is usedboth for completely restoring and partially restoring the drive unit.

The locking means cited comprises a locking member and a locking countermember which, in a mutual locking mesh, prevent the drive unit frombeing adjusted towards its dosing starting position, but allow it to beadjusted towards its dosing end position. The locking member is coupledto the drive unit, preferably rigidly. The locking counter member ispreferably connected to the casing, secured against rotating but suchthat it can slide towards and away from the locking member, wherein itis loaded towards the locking member by a spring force. The locking meshis advantageously formed by a latching connection comprising a number oflatching positions which the locking member and the locking countermember can assume relative to each other. This allows the product dosageto be delivered to be selected in discrete increments.

In some preferred embodiments, to be able to correct an inadvertentoverdose a release element is provided which, when operated, can releasethe locking mesh, engagement or connection. In order to enable thedosage to be corrected in increments, i.e., in order to be able totransfer the locking member and the locking counter member, relative toeach other, from the last latching position just assumed into thelast-but-one latching position assumed immediately before that, thelocking member forms a mechanical stopper which cooperates with therelease element. Once the locking mesh in the last latching position hasbeen released by operating the release element, the locking member isretracted by the spring force of the restoring spring towards thelast-but-one latching position. The stopper of the locking member isformed such that the stopper pushes against the release element beforethe locking member and the locking counter member have retracted beyondtheir last-but-one latching position. The release element simultaneouslyfulfils the tasks of releasing the locking mesh and forming a mechanicalstopper to limit the reverse movement of the locking member andtherefore ultimately the restoring movement of the drive unit. Since thelocking member and the locking counter member are arranged in a transfersection between the restoring spring and the drive unit, the restoringspring is used not only to completely restore the drive unit but also toreduce the product dosage in increments.

In some preferred embodiments, the dosing member, the restoring springand the locking means are arranged alongside the drive unit andpreferably likewise perform the delivering movement of the drive unit.The drive unit, dosing member, restoring spring and locking means arepreferably moved as a whole and do not change their positions relativeto each other.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of describing exemplaryembodiments, including preferred embodiments, with reference to theaccompanying Figures.

FIG. 1 depicts one embodiment of a device in accordance with theinvention;

FIG. 2 depicts a portion of the device of FIG. 1, in a longitudinalsection;

FIG. 3 depicts the portion of FIG. 2, in a perspective view;

FIG. 4 depicts an embodiment of locking means for the device of thepresent invention;

FIG. 5 depicts the locking means of FIG. 4, in a perspective view;

FIG. 6, including FIGS. 6 a and 6 b, depicts a locking member of thelocking means, in cross-section;

FIG. 7 depicts a second embodiment of the device in accordance with theinvention;

FIG. 8 depicts an embodiment of locking means for the device depicted inFIG. 7; and

FIG. 9 depicts a development of the device according to FIG. 1.

DETAILED DESCRIPTION

FIG. 1 shows a device for administering an injectable product in doses,which is formed as a so-called injection pen. the pen comprises a casingwith a front casing portion 1 comprising a receptacle 2 for a containercontaining the product. The container is preferably formed by an ampoulein which a piston 35 (see FIG. 2) is arranged such that it can slide.The container is inserted into the receptacle 2 and then points via acontainer outlet towards a proximal outlet 3 of the receptacle 2 whichfaces the injection point during an injection. By advancing the piston35 towards the outlet 3, product—for example, insulin—is displaced fromthe container and delivered through a connected catheter or an injectionneedle protruding directly from the receptacle 2, via the outlet 3. Itshould be understood that the needle can be of any size, including 31G,or larger or smaller than 31G.

In order to advance the piston 35 in the container towards the outlet 3,a driven member 4 is pressed against the rear side of the piston 35. Thedriven member fulfils the function of a piston rod and, as the productis delivered, performs the same delivering movement as the piston 35.The driven member 4 is held with other components on a rear casingportion 10 which is accommodated by the front casing portion 1 such thatit can slide linearly back and forth and protrudes from the casingportion 1 via a distal end. By pressing against the distal end of therear casing portion 10, the driven member 4 is advanced towards theoutlet 3 until it initially abuts the piston 35 and as it moves furtherforwards, advances the piston 35 in the container. This deliveringmovement of the driven member 4 is limited in the proximal direction bya mechanical stopper between the front casing portion 1 and the rearcasing portion 10. Due to its function, the rear casing portion 10 willalso be referred to below as the operating means. During the deliveringmovement, a pressure spring 8 is tensioned. Once the pressure has beentaken off the operating means 10, the tensioned pressure spring 8 pushesthe operating means 10 together with the driven member 4 back into adistal end position again. In the distal end position, the productdosage to be delivered is selected by adjusting a slight gap between thedriven member 4 and the piston 35. In adjusting the gap, i.e., dosing,the driven member 4 is moved towards the piston 35 relative to theoperating means 10.

As may be seen in FIG. 2, the product is dosed by means of a spindledrive. The driven member 4 is the starting stage or driven stage of adrive unit formed by a spindle drive which for the purpose of dosing issingle-stage. A supporting member 6 forms the supporting stage of thespindle drive. The supporting member 6 is formed by a sleeve comprisingan inner thread at a proximal end. The driven member 4 is a threaded rodcomprising an outer thread extending over almost the entire length. Thesupporting member 6 coaxially surrounds the driven member 4. The outerthread of the driven member 4 and the inner thread of the supportingmember 6 engage with each other. The supporting member 6 is arrangedbetween the pressure spring 8 and a distal equalizing spring 9. Theequalizing spring 9 causes length equalization; however, the supportingmember 6 pushes with its distal end against the operating means 10during the delivering movement, such that a delivering movement of apredetermined length is performed despite the equalizing spring 9.

In one embodiment, a dosing means comprising a locking means 20 isarranged alongside the axis of the delivering movement. The dosing meanscomprises a dosing button 11 which may be rotated relative to the casingportions 1 and 10, about an axis parallel to the axis of the deliveringmovement. The user adjusts the product dosage to be delivered using thedosing button 11. A shaft 12 extends centrally through the dosing button11 and is provided with a toothing on its outer surface. The dosingbutton 11 comprises an inner toothing which engages with the outertoothing of the shaft 12, such that a connection which is securedagainst rotating is established between the dosing button 11 and theshaft 12. However, the shaft 12 can slide back and forth relative to thedosing button 11, in the longitudinal direction of the shaft. At itsdistal end, the shaft 12 mates with a dosing member 13 having an innertoothing. The ratio of number of teeth between the outer toothing of theshaft 12 and the inner toothing of the dosing member 13 is 1:2. Thedosing member 13 further comprises an outer toothing on its outersurface. The outer toothing of the dosing member 13 is in a matingtoothed mesh or engagement with an outer toothing of another dosingmember 14 which directly transfers the rotational movement to the driveunit, onto its driven member 4 in the exemplary embodiment, and istherefore referred to below as the transfer member 14.

The transfer member 14 coaxially surrounds the driven member 4. Thedriven member 4 extends through the transfer member 14 and is guided bythe transfer member 14, such that the driven member 4 can be slid in thelongitudinal direction relative to the transfer member 14 but cannot berotated about its longitudinal axis. The transfer member 14 cannot beslid on the supporting member 6 but is fixed to it such that it canrotate about the longitudinal axis. When the transfer member 14 rotatesabout the common longitudinal axis of the driven member 4 and thesupporting member 6, the driven member 4 is therefore rotationallyslaved and, as a result of the threaded mesh with the supporting member6, is slid in the longitudinal direction relative to the supportingmember 6.

A prerequisite, however, for sliding the driven member 4 by a definedpath length in the longitudinal direction relative to the supportingmember 6 by rotating the transfer member 14 is that the supportingmember 6 is for its part secured against being rotationally slaved. Thesupporting member 6 is secured against rotating by a toothed mesh with amounting body 17 arranged alongside the supporting member 6. Themounting body 17 may be rotated relative to the casing about an axiswhich is parallel to the longitudinal axis of the supporting member 6.In this embodiment, the rotational axis of the mounting body 17coincides with the rotational axis of the dosing member 13 which, whilepreferred, is not absolutely necessary. The mounting body 17 is securedrelative to the casing in the rotational angular position assumed. Themounting body 17 is formed as a toothed wheel having an outer toothingand is in a toothed mesh with a toothed wheel 7 which surrounds thesupporting member 6 and is connected to the supporting member 6, securedagainst rotating. By securing the mounting body 17 against rotating, andby the toothed mesh with the toothed wheel 7, the rotational block isestablished for the supporting member 6. While toothed surfaces aredepicted, it should be appreciated that any suitable complementaryengaging mechanisms, arrangements or surfaces may be used.

A restoring spring 16 is supported on the mounting body 17. As may beseen more clearly in FIGS. 3 and 5, the restoring spring 16 is formed bya spiral spring comprising coils surrounding each other spirally. Thespiral spring 16 is supported on the mounting body 17 via an outerspring end and on a shaft 15 via an inner spring end, said shaft 15being connected, rotationally rigidly, to the dosing member 13. In theexemplary embodiment, the dosing member 13 and the shaft 15 are formedas one piece, the shaft 15 projecting centrically from the dosing member13 and extending parallel to the longitudinal axis of the driven member14, into the mounting body 17. The restoring spring 16 is wound aroundthe distal end of the shaft 15 from its inner spring end to the outerspring end. The restoring spring 16 is thus supported on the shaft 15and the mounting body 17 such that, when the dosing member 13 is rotatedrelative to the mounting body 17, the restoring spring 16 is tensionedor relaxed depending on the direction of rotation. Due to the couplingbetween the drive unit 4 and the dosing member 13, and the rotationalblock between the mounting body 17 and the supporting member 6, or moregenerally still the casing, the restoring spring 16 is ultimatelyclamped between the driven member 4 and the supporting member 6, i.e.,between the members which rotate relative to each other in order toretract the driven member 4 from a dosing end position towards or up toa dosing starting position. The dosing starting position is understoodhere as any position of the driven member 4, relative to the piston,from which the driven member 4 is moved towards the piston during adelivering movement, without delivery actually taking place. Whenselecting the product dosage to be delivered, i.e., when dosing, thedriven member 4 is moved from such a dosing starting position towardsthe piston and a slight gap between the driven member 4 and the pistonis thereby reduced. The restoring spring 16 is then arranged such thatit is tensioned by this adjusting movement of the drive unit and relaxedby a reverse movement towards the dosing starting position.

FIG. 4 shows one embodiment of locking means 20 which is connected tothe dosing member 13 in an enlarged representation. In latchingpositions of the locking means 20, the spring force of the tensionedrestoring spring 16 is taken off the dosing member 13, and consequentlyoff the driven member 4, by the locking means 20.

The locking means 20 comprises a locking member 21 and a locking countermember 24. The locking member 21 is a disc-shaped locking wheel which isconnected to the dosing member 13, secured against rotating. In theexemplary embodiment, it is fixed to the dosing member shaft 15, securedagainst rotating. The locking counter member 24 is formed as an annulardisc through which the dosing member shaft 15 extends. The lockingcounter member 24 is connected to the casing portion 10, secured againstrotating, and guided relative to the casing portion 10 such that it canmove back and forth along the dosing member shaft 15. Grooves 26 servesas the rotational block and linear guide and extend on the outer surfaceof the locking counter member 24 in the longitudinal direction andengage with the corresponding guide protrusions of the casing portion10.

On facing sides opposite each other, the locking member 21 and thelocking counter member 24 each comprise saw teeth 22 and 25 arranged inuniform distribution over a circle which is concentric with respect tothe dosing member shaft 15. The saw teeth 22 of the locking member 21and the saw teeth 25 of the locking counter member 24 are arranged suchthat the gradually ascending flanks of all the saw teeth 22 alwayssimultaneously slide over the gradually ascending flanks of the sawteeth 25 when the dosing member 13 is rotated such that the drive unitis adjusted towards a dosing end position. In order to enable thesliding movement of the saw teeth 22 and 25, the locking counter member24 can be pushed away from the locking member 21 against the restoringforce of a supporting spring 27. As soon as the saw teeth 22 and 25 haveslid over each other via their flat, gradually angled or ascendingflanks, the locking counter member 24 snaps back forward against thelocking member 21 due to the spring force of the supporting spring 27.The locking member 21 and the locking counter member 24 are preventedfrom rotating relative to each other in the opposite direction by thefact that the steep flanks of the saw teeth 22 and 25 oppose each otherwith respect to the opposing direction and the locking member 21 is thusprevented from reversing. Rotating the locking member 21 further, fromone latching position to the next latching position, corresponds to asettable dosage unit.

The locking means 20 does not only serve to completely prevent the driveunit from being restored. In the event of overdosing, a dosage which hasbeen erroneously adjusted too high can be reset again unit by unit withthe aid of the locking means 20. In resetting, a release element 28 andstoppers 23 formed on the locking member 21 cooperate.

As may be seen from FIGS. 4 and 5 and the cross-section A—A in FIG. 6,including FIGS. 6 a and 6 b, the stoppers 23 are formed by a serratedrim on the outer surface of the locking member 21. The serrated rim isformed by linear grooves which are let into the outer surface area ofthe locking member 21 and continuously extend axially from one facingside of the locking member 21 to the other. The stoppers 23 are eachformed by one of the two groove walls facing each other when viewed inthe circumferential direction. The release element 28 is a slider whichis arranged on the casing portion 10 such that it can be slid into thegrooves of the locking member 21, towards the locking counter member 24,and slid out again from said grooves. It is inserted against a springforce, such that the release element 28 is automatically moved out ofthe groove mesh again once it is released. The sliding direction isindicated in FIGS. 4 and 5 by a double arrow. The release element 28exhibits a width, measured in the circumferential direction of thelocking member 21, which is smaller than the width of the grooves of thelocking member 21. Once the release element 28 has been inserted intoone of the grooves, a slight gap remains between the stopper 23 formedon the locking member 21 and the opposing area of the release element28, as may best be seen in the cross-section in FIG. 6.

The functionality or operation of the device of the first embodiment isexplained as follows:

As shown in FIG. 2, the drive unit assumes its first dosing startingposition before a first delivery and a first dosing. A containeraccommodated in the receptacle 2 is still completely full. The firstdosing is made from this first dosing starting position. To this end,the dosing button 11 is rotated relative to the casing (FIG. 1). Byrotating the dosing button 11, the shaft 12 is rotationally slaved. Theshaft 12 mates with the inner toothing of the dosing member 13. Due tothe ratio of number of teeth, which may be varied, the rotationalangular speed of the shaft 12 is reduced in a ratio of 2:1 whentransferred to the dosing member 13. The dosing member 13 mates with thetransfer member 14 in a ratio of 1:1.

When rotated, the transfer member 14 slaves the connected driven member4, secured against rotating. The supporting member 6 is held in itsrotational angular position relative to the mounting body 17 andrelative to the casing due to the toothed mesh between the toothed wheel7 and the mounting body 17 and the fact that the mounting body 17 issecured against rotating relative to the casing. As a result of thethreaded mesh between the driven member 4 and the supporting member 6,the rotating driven member 4 is moved towards the outlet 3.

The rotational movement and the non-rotating connection between thedosing member 13 and the shaft 15 tensions the restoring spring 16 onthe one hand and rotationally slaves the locking member 21 relative tothe locking counter member 24 on the other. The saw toothed mesh and thespring movement of the locking counter member 24 back and forth enablethe locking member 21 and the locking counter member 24 to rotaterelative to each other. They are prevented, however, from reversing dueto the saw toothed mesh. Furthermore, the saw toothed mesh generates aneasily audible clicking sound which makes each increase by one dosingunit audible to the user. In addition, an optical display of the numberof dosing units cumulatively selected in said dosing is preferablyprovided, based on electronically detecting the rotational angularposition of one of the members rotated during dosing.

Once the dosage is selected, the supporting member 6 is advanced withthe driven member 4, together with the other components of the dosingmeans including the locking means 20, relative to the casing portion 1,towards the outlet 3 up to the proximal end position of the operatingmeans 10, by manually pressing against the operating means 10. In thecourse of this delivery movement, the driven member 4 initially pushesagainst the piston, which is advanced in the container towards theoutlet 3 when the driven member 4 is advanced further. By advancing thepiston, an amount of product corresponding to the dosage set isdisplaced from the container and delivered through the outlet 3 and aconnected injection needle. As soon as the pressure is taken away fromthe operating means 10, the operating means 10 moves back to its distalend position again due to the pressure of the pressure spring 8. In thedistal end position of the operating means 10, the driven member 4 thenassumes its new dosing starting position for another dosing and productdelivery. This process, i.e., dosing and subsequent delivery movement,can be repeated a number of times, until the driven member 4 hasperformed the delivery movement after reaching its last dosing endposition and the container is, ideally, completely empty.

In one embodiment, at the end of the delivery movement, the shaft 12pushes against a switch connected to an optical display, which resetsthe display to “0”. The mesh between the dosing member 13 and the shaft12 is correspondingly secured against rotating, such that the shaft 12participates in all the sliding movements of the dosing member 13.

In order to use the device again, the driven member 4 has to beretracted from the last dosing end position, preferably up to its firstdosing starting position. The restoring movement is automaticallyperformed by means of the restoring spring 16, when the rotational blockbetween the mounting body 17 and the rear casing portion 10 is released.To this end, a release element of its own is provided, for example,another slider which engages with the mounting body 17 to establish therotational block and is disengaged from the mounting body 17 when therotational block is released. Once the rotational block has beenreleased, the mounting body 17 rotates about a rotational axis whichcoincides with that of the dosing member 13 due to the stored springenergy. Due to the facing mesh or engagement with the mounting body 17,the toothed wheel 7 and the supporting member 6 connected to it, securedagainst rotating, are necessarily rotationally slaved. The locking meshbetween the locking member 21 and the locking counter member 24 securesthe dosing member 13 in the rotational angular position assumed relativeto the rear casing portion 10. Due to the toothed mesh, the transfermember 14 and the drive member 4 connected to it, secured againstrotating, also retain their rotational angular positions assumed. Due tothe relative rotation between the supporting member 6 and the drivenmember 4 enforced in this way, the driven member 4 is inserted into thesupporting member 6 as far as its first dosing starting position. Inthis first dosing starting position, the restoring spring 16 ispreferably biased, in order to ensure that the driven member 4 iscompletely retracted, even after the device has been used a number oftimes.

If, while dosing, i.e., during the adjusting movement of the drive unitfrom a dosing starting position to the next dosing end position, theuser has inadvertently selected too many dosing units, this overdose canbe corrected by means of the release element 28. To effect this, therelease element 28 is pushed into the axially opposing groove of thelocking member 21, against the pressure of a spring, and pushed furtherup to the locking counter member 24, until the locking counter member 24protrudes beyond the locking member 21, against the pressure of thesupporting spring 27. The release element 28 can be advanced against thelocking counter member 24 until the mutually opposing steep flanks ofthe saw teeth 22 and 25 (FIG. 4) in the latching position assumeddisengage. As soon as this locking mesh is released, the locking countermember 24 rotates counter to the direction of rotation when increasingthe dosage, due to the spring force of the restoring spring 16.Reversing the locking member 21 is limited, however, by the releaseelement 28. For the locking member 21 can only be reversed by the slightgap remaining between the release element 28 and the stopper 23 formedby the opposing groove wall. If the release element 28 is released, thenit retracts again due to the spring force bearing on it and ultimatelyleaves the groove of the locking member 21. During this movement, thelocking counter member 24 is initially pressed against the lockingmember 21 again by the supporting spring 27. As soon as the releaseelement 28 has completely left the groove of the locking member 21 andthe pair of stoppers 23, 28 have been released, the locking member 21reverses further due to the spring force of the restoring spring 16,until the mutually opposing steep tooth flanks of the saw teeth 22 and25 abut each other. Reversing the locking member 21 by operating therelease element 28 corresponds to resetting by one dosing unit.

FIG. 7 shows a longitudinal section of the parts of a device accordingto a second exemplary embodiment. In this embodiment, both adjustingmovements of the drive unit, namely the movement of the driven member 4towards the dosing end position and the movement towards the dosingstarting position, are performed by the mesh or engagement with thedosing member 13. The mounting body 17 is simply connected, securedagainst rotating, to the rear casing portion 10, and only coupled to thespindle drive via the dosing member 13. The restoring spring 16 issupported via an inner spring end on a shaft or trunnion 15 whichprojects centrically from the dosing member 13, secured againstrotating, and is connected to it. The supporting member 6 is helddirectly by the casing portion 1 (FIG. 1), secured against rotating.With respect to the drive unit and clamping the restoring spring 16,there are no other changes from the device of the first embodiment. Inthe second embodiment, the spindle drive can, however, alternatively beformed between the driven member 4 and the transfer member 14 and thesupporting member 6 can serve purely as a linear guide for the drivenmember 4 during the adjusting movement.

The locking means 20 is not, however, arranged on a shaft connected tothe dosing member 13, secured against rotating, but along the dosingshaft 12. The mesh between the shaft 12 and the dosing member 13 is,however, the same as in the device of the first embodiment.

FIG. 8 shows one embodiment of the locking means 20 in an enlargedrepresentation. The locking member 21 surrounds the shaft 12 and ismounted such that it can rotate relative to the shaft 12. The dosingbutton 11 is connected to the shaft 12, secured against rotating, as inthe first embodiment. On their facing sides, which face each other, thedosing button 11 and the locking member 21 comprise a number of catches11 a and 21 a which mesh with each other to form a rotational blockbetween the dosing button 11 and the locking member 21, as shown in FIG.8. The dosing button 11 can be moved against the force of a spring 19,away from the locking member 21, out of the rotational blocking meshformed by the catches 11 a and 21 a. The locking counter member 24 isagain mounted secured against rotating, but along the shaft 12 againstthe force of a supporting spring 27, such that it can linearly slidetowards the dosing member 13. The form and functionality of the lockingmember 21 and the locking counter member 24 is the same as in the firstembodiment, with the exception of the locking member 21 beingrotationally slaved by the dosing button 11.

With respect to the functionality, too, reference may be made to thefull content of the embodiments of the first embodiment, with theexception of completely restoring the drive unit to its first or mostdistal dosing starting position. In order to trigger the restoringmovement after reaching the last dosing end position, however, thedosing button 11 is pushed away from the locking member 21, against theforce of a spring 19, which releases the rotational block between thedosing button 11 and the locking member 21. Once the rotational block isreleased, the shaft 12, the dosing button 11 and the dosing member 13are reversed by the spring force of the restoring spring 16. During thisreversing, the driven member 4 is retracted to its most distal dosingstarting position, via the mesh with the transfer member 14.

FIG. 9 shows a third embodiment which differs from the first embodimentwith respect to the drive unit. The spindle drive of the drive unit ofthe third embodiment is two-stage, with the driven member 4 as thestarting stage, a drive member 5 as an intermediate stage and thesupporting member 6 as the supporting stage. During dosing, thesupporting member 6 is held relative to the rear casing portion 10,secured against rotating and secured against sliding, as in the othertwo embodiments.

The transfer member 14, which is rotary driven by the dosing member 13,slaves the drive member 5 when it is rotated. This advances the drivemember 5 relative to the supporting member 6, towards the outlet 3, viaa threaded mesh with the supporting member 6. As it is translated, thedrive member 5 slaves the driven member 4. In addition, the drivenmember 4 is advanced relative to the drive member 5, towards the outlet3, via a threaded mesh with the drive member 5. In order to maintain themovements of the drive member 5 and the driven member 4 relative to eachother and relative to the supporting member 6, a rotational block 29 inthe form of a disc is fixed to the distal end of the drive member 5. Itis fixed such that the drive member 5 can be rotated relative to therotational block 29, but slaves the rotational block 29 when it isitself translated relative to the supporting member 6. The rotationalblock 29 is connected to the supporting member 6, secured againstrotating, as for example shown in the section A—A, by meshing twoprotrusions with corresponding longitudinal grooves of the supportingmember 6. A pin-shaped slaving means 31 is fixed to the rotational block29, secured against rotating, for example by a screw 30. The drivenmember 4 engages with the slaving means 31 such that the driven memberis prevented from rotating relative to the slaving means 31, though itis possible for the driven member 4 to be translated relative to theslaving means 31. The driven member 4 is thus connected to thesupporting member 6, secured against rotating, via the slaving means 31and the rotational block 29. Due to the multiple stages, comprising anumber of stages 4 and 5 moved in the longitudinal direction, a spindledrive having a short design and a large dosing length is achieved.

In the foregoing description, embodiments of the invention, includingpreferred embodiments, have been presented for the purpose ofillustration and description. They are not intended to be exhaustive orto limit the invention to the precise form disclosed. Obviousmodifications or variations are possible in light of the aboveteachings. The embodiments were chosen and described to provide the bestillustration of the principals of the invention and its practicalapplication, and to enable one of ordinary skill in the art to utilizethe invention in various embodiments and with various modifications asare suited to the particular use contemplated. All such modificationsand variations are within the scope of the invention as determined bythe appended claims when interpreted in accordance with the breadth theyare fairly, legally, and equitably entitled.

1. A device for administering an injectable product in doses, saiddevice comprising: a) a casing comprising a receptacle for a containerwhich contains said product and accommodates a piston, such that saidpiston can advance toward an outlet of the container for delivering aselected product dosage; b) a dosing member which can perform a dosingmovement relative to said casing for selecting said product dosage,wherein a user of the device adjusts the dosing member for selecting theproduct dosage for each administration; c) a drive unit coupleable tothe casing and said dosing member such that said drive unit can beadjusted relative to the casing from a dosing starting position to adosing end position by the dosing movement of the dosing member; d)operating means for causing the drive unit to perform a deliveringmovement by which the piston is advanced toward said outlet; e) arestoring spring in a tensioned state coupled to the drive unit by arelease whereby it can selectively cause a restoring movement of thedrive unit towards its dosing starting position; and f) a releaseelement configured for correcting an inadvertent overdose.
 2. The deviceas set forth in claim 1, wherein said restoring spring is tensioned byadjusting the drive unit towards the dosing end position, and a lockingmeans prevents the drive unit from being restored.
 3. The device as setforth in claim 1, wherein the restoring spring comprises a spiral springclamped between the casing and a rotating member which can be rotatedrelative to the casing, said rotating member and the restoring springbeing tensioned when the drive unit is adjusted.
 4. The device as setforth in claim 3, wherein the rotating member advances a driven memberof the drive unit via a spindle drive towards the piston during thedosing movement.
 5. The device as set forth in claim 4, wherein saidspindle drive comprises a supporting member which is mounted such thatit can rotate relative to the casing, but is secured against rotating,from which it can be released.
 6. The device as set forth in claim 4,wherein the driven member extends through the dosing member and isguided by the dosing member such that the driven member may be slid inthe longitudinal direction relative to the dosing member but may not berotated about a longitudinal axis.
 7. The device as set forth in claim1, further comprising locking means in a locking mesh for preventing thedrive unit from being restored, wherein the restoring spring is clampedbetween a mounting body and a rotating member, said rotating memberrotated when the drive unit is adjusted, wherein said mounting body ismounted such that it can rotate relative to the casing and engages withthe drive unit for rotary driving, said locking means comprising areleaseable rotational block which prevents the mounting body fromrotating relative to the casing.
 8. The device as set forth in claim 1,further comprising a locking member coupled to the drive unit and alocking counter member coupled to the casing, in a locking mesh, toprevent the drive unit from being restored.
 9. The device as set forthin claim 8, wherein said locking member can be latched with said lockingcounter member in latching positions, to form said locking mesh, and arelease element is provided, to release the locking mesh.
 10. The deviceas set forth in claim 9, wherein the locking member forms a stopperwhich comes to rest against said release element after the locking meshhas been released, and limits the restoring movement of the drive unit.11. The device as set forth in claim 8, wherein the locking member andthe locking counter member, in the locking mesh, are pressed againsteach other by means of a spring.
 12. The device as set forth in claim 8,wherein: the dosing movement of the dosing member is a rotationalmovement; a shaft is connected to the dosing member, said shaft rotatingwhen the dosing member is rotated; the locking member is positioned onthe shaft, secured against rotating; and the locking counter member canbe disengaged from the locking mesh along the length of the shaftagainst the force of a spring.
 13. The device as set forth in claim 1,wherein the dosing member is mounted such that it can rotate about arotational axis relative to the casing and a shaft projects from thedosing member towards the rotational axis, the restoring spring beingsupported on said shaft.
 14. The device as set forth in claim 1, furthercomprising a dosing button is associated with the casing such that itcan rotate, said dosing button engaging a shaft such that a rotationalmovement of the dosing button causes a rotational movement of the shaftand the shaft can slide longitudinally relative to the dosing button,said shaft engaging the dosing member to generate the dosing movement ofthe dosing member.
 15. The device as set forth in claim 1, wherein thedosing member and the restoring spring are arranged alongside the driveunit in the casing.
 16. The device as set forth in claim 1, wherein therestoring spring is also configured to reduce the selected productdosage in increments.
 17. The device as set forth in claim 1, whereinthe release element is formed on a locking member.
 18. A device foradministering an injectable product in doses comprising: a casing havinga receptacle for a container which contains the product and accommodatesa piston such that the piston can advance towards an outlet of thecontainer for delivering a selected product dose; a dosing membermoveable relative to the casing for selecting the product dose, whereina user of the device adjusts the dosing member for selecting the productdosage for each administration; a drive unit coupleable to the casingand the dosing member such that the drive unit can be adjusted relativeto the casing from a dosing starting position to a dosing end positionby moving the dosing member; an operating mechanism which causes thedrive unit to perform a delivering movement by which the piston isadvanced towards the outlet; a restoring spring in a tensioned statereleasably coupled to the drive unit for causing a restoring movement ofthe drive unit toward the dosing starting position when released; and arelease element configured for correcting an inadvertent overdose. 19.The device as set forth in claim 18, wherein the restoring spring isalso configured to reduce the selected product dosage in increments.